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The Cipher Atlas

Every ciphered letter this site has read or tried to read, drawn as an arc from where it was written to where it was sent. Press play to watch five centuries of secret diplomacy cross the map, from a Florentine commissioner at Urbino in 1425 to a German police radio net on the Eastern Front in 1942. Hover an arc for the letter, click it for the write-up.

The mapBusiest routesAbout the dataThe key web

Daniel Bourdeau · posted

Correspondents
1425
142015001600170018001945

Busiest routes

The same few lines carry most of the traffic: the nuncios writing home to Rome, the ambassadors of the Habsburgs and of France, and the Dutch envoys reporting to The Hague. Click a route to isolate it on the map, or a city on the map to see the routes through it.

About the data

Each arc is one document from a target's profile.json, the record kept for every cipher on this site. It is placed at the city where the letter was written and the city it was sent to, as the notes state them. A court or a person is placed where they were at that date. Letters whose sender or recipient cannot be located from the evidence are left off rather than guessed. So are the cryptograms with no route at all, such as Voynich, Scorpion and the gold bars. The coastlines are modern (Natural Earth); the map draws no frontiers, because they moved too often over five centuries. Colour gives the outcome of the write-up: read, explained or found already read, read in part, attempted.